Cortactin regulates cofilin and N-WASp activities to control the stages of invadopodium assembly and maturation.

Invadopodia are matrix-degrading membrane protrusions in invasive carcinoma cells. The mechanisms regulating invadopodium assembly and maturation are not understood. We have dissected the stages of invadopodium assembly and maturation and show that invadopodia use cortactin phosphorylation as a master switch during these processes. In particular, cortactin phosphorylation was found to regulate cofilin and Arp2/3 complex-dependent actin polymerization. Cortactin directly binds cofilin and inhibits its severing activity. Cortactin phosphorylation is required to release this inhibition so cofilin can sever actin filaments to create barbed ends at invadopodia to support Arp2/3-dependent actin polymerization. After barbed end formation, cortactin is dephosphorylated, which blocks cofilin severing activity thereby stabilizing invadopodia. These findings identify novel mechanisms for actin polymerization in the invadopodia of metastatic carcinoma cells and define four distinct stages of invadopodium assembly and maturation consisting of invadopodium precursor formation, actin polymerization, stabilization, and matrix degradation.

Fiebre por dengue asociada acolecistitis alitiásica / Dengue fever related acalculous acolecistitis

Contexto: El dengue representa un importante problema de salud pública en países con climas tropicales ysubtropicales. En su forma clásica se manifiesta con fiebre, mialgias, artralgias, dolor retroauricular y malestar general; no obstante, cuadros atípicos de síndrome febril pueden complicar el diagnóstico.Presentación del caso: Reportamos el caso de una mujer en edad fértil que se presentó con un cuadro febril de48 horas de evolución acompañado de dolor abdominal, malestar general y evidencia ecosonográfica decolecistitis alitiásica. Al décimo día de evolución se encontraron anticuerpos de tipo IgG e IgM anti-Dengue; por locual, se concluyó el diagnóstico de Fiebre de Dengue acompañada de colecistitis alitiásica.Conclusión: Es importante tener presente el diagnóstico de dengue en pacientes febriles que han viajadorecientemente a regiones tropicales y subtropicales o que residan en ellas, incluso en quienes su cuadro clínicono concuerde con la descripción clásica de la enfermedad.

Effect of the tropical grass Brachiaria brizantha (Hochst. ex A. Rich.) Stapf on microbial population and activity in petroleum-contaminated soil.

The effect of the tropical pasture grass Brachiaria brizantha on numbers of bacteria, fungi and degraders of alkanes, aromatics, cycloalkanes and crude oil in petroleum hydrocarbon contaminated and uncontaminated savannah soil was evaluated. Substrate induced soil respiration and soil pH were compared between planted and unplanted soil. B. brizantha had a mostly increasing effect on microbial numbers. As an exception, growth of bacteria was not or negatively affected. Microbial respiration and pH were always lower in planted than in unplanted soil. Low pH may result from enhanced oil degradation in planted soil leading to an accumulation of organic acids. A comparable stimulation of crude oil degraders and fungi in planted soil points to the importance of fungi. Since they tolerate lower pH values than bacteria, they are considered to play a central role in oil degradation. Given that the enhancement of crude oil degradation under the influence of B. brizantha could not clearly be correlated to microbial numbers and activity, other factors like oxygen availability, plant enzymes and synergistic degradation by microbial consortia have to be considered.

Influence of fertilizer levels on phytoremediation of crude oil-contaminated soils with the tropical pasture grass Brachiaria brizantha (hochst. ex a. rich.) stapf.

Determination of fertilizer levels in phytoremediation of petroleum hydrocarbons is a complex issue, since nutrient demands of the plant and of degrading microorganisms in the rhizosphere have to be considered In the present work, three fertilizer levels were tested in a greenhouse experiment with the aim of optimizing growth of the tropical pasture grass Brachiaria brizantha and enhance microbial degradation of heavy crude oil in soil Fertilizer was applied twice in a concentration of 200, 300, and 400 mg each of N, P, and K per kg soil before and after the first sampling (14 wk). The medium fertilizer concentration resulted in best root growth and highest absolute oil dissipation (18.4%) after 22 wk The highest concentration produced best shoot growth and highest relative oil dissipation after 14 wk (10.5% less than unplanted control). In general, degradation of total oil and grease was higher in planted than in unplanted soil, but differences diminished toward the end of the experiment. Next to fertiizer quantity, its composition is an important factor to be further studied, including the form of available nitrogen (N-NO3- vs. N-NH4+). Field trials are considered indispensable for further phytoremediation studies, since greenhouse experiments produce particular water and nutrient conditions.

Absence of selectivity in the loss of neurons from the developing cortical subplate of the rat.

Neurons of the cortical subplate display evidence of cell death, although a significant population survives to the mature brain. The present study examined different populations of neurons to determine if the loss of cells was specific for a particular cell type. Immunocytochemical procedures for neurons expressing GluR2/3, GAD, or NPY, were used on tissue sections taken from animals at gestational day 18 to postnatal day 21. The rate of loss of labeled cells was similar for all groups of neurons. Thus, these data reveal no evidence that the loss of subplate neurons is specific to any major cell type.